fix UnicodeDecodeError

UnicodeDecodeError: 'ascii' codec can't decode byte 0xc3 in position 42103: ordinal not in range(128)

update_checker.py

@@ -93,7 +93,7 @@ json.dump(allFirmwareDownloads,open("firmwareDownloads.json","w"),sort_keys=True
 nodesdbFilename = "/home/www/html/netinfo/json/nodesdb.json"
 if not os.path.isfile(nodesdbFilename):
     nodesdbFilename = "nodesdb.json"
-data = json.load(open(nodesdbFilename))
+data = json.load(open(nodesdbFilename, encoding='utf-8'))
 
 for download in allFirmwareDownloads:
     try: